The invention relates generally to medical devices and procedures. More particularly, the invention relates to adjustable surgical cables and methods for treating spinal stenosis.
Spinal stenosis is a progressive narrowing of the spinal canal that causes compression of the spinal cord and nerve roots extending from the spinal cord. Each vertebra in the spinal column has an opening extending therethrough. The openings of the vertebrae are aligned vertically to form the spinal canal, within which the spinal cord is disposed. As the spinal canal narrows from spinal stenosis, the spinal cord and nerve roots extending from the spinal cord and between adjacent vertebrae are compressed and may become inflamed. Spinal stenosis can cause pain, weakness, numbness, burning sensations, tingling, and in particularly severe cases, may cause loss of bladder or bowel function, or paralysis.
Mild cases of spinal stenosis may be treated with rest or restricted activity, non-steroidal anti-inflammatory drugs (e.g., aspirin), corticosteroid injections (epidural steroids), and/or physical therapy. In certain instances the compression of the nerve roots may be surgically corrected (e.g., via a decompressive laminectomy) as the patient has increasing pain. In some known surgical procedures, bone and other tissue that has impinged upon the spinal canal and/or exerted pressure on the spinal cord can be removed. In other known surgical procedures, two adjacent vertebrae may be fused to prevent an area of instability, improper alignment or slippage, such as that caused by spondylolisthesis. In yet other known surgical procedures, spacers and/or surgical cables can be disposed between and/or about adjacent spinous processes to limit the movement between adjacent vertebrae.
Such known procedures, however, are not well suited to treat spinal stenosis in the L5-S1 location of the spinal column because the sacrum does not include a spinous process having sufficient area to support implants, tethers or the like. Moreover, known procedures that employ surgical cables often include wrapping the cable about a bone structure in a manner that limits both flexion and extension of the spinal column.
Thus, a need exists for improved surgical cables and methods for treating spinal stenosis. More particularly, a need exists for methods for treating spinal stenosis in the L5-S1 location.